diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-07-29 14:23:07 -0400 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2025-07-31 10:20:04 -0400 |
| commit | b9c73524106e1c0c857006fb9ff2e5a510dc4021 (patch) | |
| tree | 12252b92ffad517ceb6ed158c8d39d05e05dd017 /include/linux | |
| parent | 5e32d0f15cc5c843a4115c4644d984d42524c794 (diff) | |
unwind_user/deferred: Add unwind cache
Cache the results of the unwind to ensure the unwind is only performed
once, even when called by multiple tracers.
The cache nr_entries gets cleared every time the task exits the kernel.
When a stacktrace is requested, nr_entries gets set to the number of
entries in the stacktrace. If another stacktrace is requested, if
nr_entries is not zero, then it contains the same stacktrace that would be
retrieved so it is not processed again and the entries is given to the
caller.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/20250729182405.319691167@kernel.org
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-By: Indu Bhagat <indu.bhagat@oracle.com>
Co-developed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/entry-common.h | 2 | ||||
| -rw-r--r-- | include/linux/unwind_deferred.h | 8 | ||||
| -rw-r--r-- | include/linux/unwind_deferred_types.h | 7 |
3 files changed, 16 insertions, 1 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index f94f3fdf15fc..8908b8eeb99b 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -12,6 +12,7 @@ #include <linux/resume_user_mode.h> #include <linux/tick.h> #include <linux/kmsan.h> +#include <linux/unwind_deferred.h> #include <asm/entry-common.h> #include <asm/syscall.h> @@ -362,6 +363,7 @@ static __always_inline void exit_to_user_mode(void) lockdep_hardirqs_on_prepare(); instrumentation_end(); + unwind_reset_info(); user_enter_irqoff(); arch_exit_to_user_mode(); lockdep_hardirqs_on(CALLER_ADDR0); diff --git a/include/linux/unwind_deferred.h b/include/linux/unwind_deferred.h index a5f6e8f8a1a2..baacf4a1eb4c 100644 --- a/include/linux/unwind_deferred.h +++ b/include/linux/unwind_deferred.h @@ -12,6 +12,12 @@ void unwind_task_free(struct task_struct *task); int unwind_user_faultable(struct unwind_stacktrace *trace); +static __always_inline void unwind_reset_info(void) +{ + if (unlikely(current->unwind_info.cache)) + current->unwind_info.cache->nr_entries = 0; +} + #else /* !CONFIG_UNWIND_USER */ static inline void unwind_task_init(struct task_struct *task) {} @@ -19,6 +25,8 @@ static inline void unwind_task_free(struct task_struct *task) {} static inline int unwind_user_faultable(struct unwind_stacktrace *trace) { return -ENOSYS; } +static inline void unwind_reset_info(void) {} + #endif /* !CONFIG_UNWIND_USER */ #endif /* _LINUX_UNWIND_USER_DEFERRED_H */ diff --git a/include/linux/unwind_deferred_types.h b/include/linux/unwind_deferred_types.h index aa32db574e43..db5b54b18828 100644 --- a/include/linux/unwind_deferred_types.h +++ b/include/linux/unwind_deferred_types.h @@ -2,8 +2,13 @@ #ifndef _LINUX_UNWIND_USER_DEFERRED_TYPES_H #define _LINUX_UNWIND_USER_DEFERRED_TYPES_H +struct unwind_cache { + unsigned int nr_entries; + unsigned long entries[]; +}; + struct unwind_task_info { - unsigned long *entries; + struct unwind_cache *cache; }; #endif /* _LINUX_UNWIND_USER_DEFERRED_TYPES_H */ |